With advantages of high efficiency, long service life, all solid-state, electro luminescence, small size and environmental friendliness, light emitting diodes (LEDs) are known as the fourth generation of lighting sources or the energy-saving lighting sources and are widely applied in indication, display, decoration, backlight, general lighting, urban night lights, etc.
For LED chips with sapphire and AlN non-conductive substrates, thermal conductivity of the substrate is low, resulting in high temperature of the PN junction in lateral LEDs. To improve heat dissipation, a flip-chip structure with higher light emitting efficiency is proposed.